This invention generally relates to an impeller for a rotary slicing machine for cutting food products and the like into slices. More particularly, this invention relates to an impeller for a rotary slicing machine, wherein the impeller has angled paddles that are arranged to transport, align and centrifugally throw out a food product in a radial direction within a drum type slicing machine so as to be cut by a fixed slicing blade mounted adjacent to the path of motion of the impeller and food product.
Food slicing machines of various types are used to cut, slice, dice and otherwise reduce the size of larger food products into smaller pieces depending upon the configuration of various knives carried by the machine. One type of a food slicing machine is a rotary slicing machine such as shown in U.S. Pat. No. 3,521,688, granted Jul. 28, 1970 to Urschel et al.
A conventional rotary slicing machine includes an open ended, generally annular impeller that is mounted for rotation in a non-rotating drum formed by a stationary housing of the machine. The impeller is rotatably driven about an axis coincident with the cylindrical axis of the drum to centrifugally throw the food products in a radially outward direction. Since the slicing operation is continuous, the impeller paddles are constantly moving in a circular path about the interior surface of the drum so as to carry the food products past a stationary slicing blade to cut the food products into slab-like slices. The slices are immediately guided into a cross-cut assembly where they are cut into strips.
An impeller adapted for use in such a rotary slicing machine must accommodate a variety of shapes and sizes of food products, especially vegetable products. A conventional impeller is shown and described in U.S. Pat. No. 3,196,916 granted Jul. 27, 1965 to Urschel. The impeller generally comprises a rear base plate and an forward ring that is permanently secured in axially spaced parallel relation to the base plate by a plurality of generally straight, planar and circumferentially spaced paddles. The paddles extend both radially and longitudinally to provide relatively large openings which diverge radially outwardly. Pockets for carrying food products are formed between adjacent paddles. The impeller is mounted within the drum for rotational movement of the paddles about an axis coincident with the cylindrical axis of the drum such that a portion of the paddles near the peripheries of the ring and the base sweep the interior surface of the drum. The paddles are arranged so they extend generally parallel with a slicing blade carried by the housing of the rotary slicing machine.
Food products are mostly fed into the rotary impeller in an orientation generally parallel with the horizontal axis of rotation. As the food products are fed into the impeller, the food products fall into a pocket in an orientation whereby a major axis of the food products lies generally parallel with the axis of the paddle. Generally, the impeller rotates about 225° from the point at which the food products are fed into the impeller until they urged against the stationary slicing blade carried by the outer housing at the periphery of the impeller. The impeller carries food products rotationally around the drum for repeated slicing engagement with the stationary slicing blade along its major axis so that the food products are sliced into a plurality of slices. It should be noted that the conventional impeller can be arranged for rotation about either a vertical or a horizontal axis, depending on the configuration of the rotary slicing machine, and more than one slicing blade can be used.
Such rotary slicing machines are of particular use for cutting whole potatoes into a plurality of slices which are delivered to a slicing system that divides the slices into french fry strips of generally uniform cross-sectional size and shape. Usually, potatoes used in preparing french fries will generally be oblong in shape and vary in size and will have a major axis and a minor axis where the major axis is the longer of the two.
Although the conventional impeller generally works well, under certain circumstances, depending upon the raw potato size, slice thickness and other variables, it has been found that a small percentage of french fries have thin, tapered and other undesirable cuts. One reason is that the conventional impeller does not consistently register a potato with either the base plate or the ring so as to reference the potato with respect to the slicing blade and the subsequent slicing and cutting operations. Another reason is that there is a tendency for some potatoes to bounce off of the paddles upon entry into the impeller, resulting in misalignment with respect to the paddles. Furthermore, as potatoes are fed into the impeller, there is a probability that potatoes may collide with one another, resulting in disorientation and potential bruising.
The effect of potato instability and the need for indexing a potato with respect to slicing and cutting apparatuses is demonstrated when a potato is first sliced by a stationary slicing knife and then by a circular knife. After a potato slab is sliced by the slicing knife, the circular knife cuts the slab along its minor axis which results in two slab portions. When a potato is not sufficiently stabilized and indexed by an impeller, there is a tendency for one slab portion to be larger than another slab portion since the potato will arbitrarily be positioned in the pocket with respect to the slicing knife. As the smaller portion proceeds from the circular knife, there is a propensity for the smaller portion to advance slower from the circular knife. Moreover, there is a tendency for the smaller portion to rotate more than the larger portion as it leaves the circular knife due to a bevel on the circular knife blade. As a result of the slower advancement and rotation of the smaller portion, there is potential for the smaller potato portions to be cut in subsequent slicing operations which may result in short, tapered and thin cuts of undesirable proportions. There exists, therefore, a need for an improved rotary impeller that sufficiently registers one end of a food product from the impeller, and orientates, aligns and stabilizes a food product so as to be routinely positioned in a desirable alignment with a slicing apparatus carried by the rotary slicing machine.
In order to overcome defects of the conventional impeller, it is known in the art to configure an impeller to carry a potato to a slicing blade in a predetermined orientation. U.S. Pat. No. 4,625,606 discloses an impeller that includes an axially centered divider ring defining a pair of annular chambers for potato passage outwardly to the slicing knife, where larger potatoes are required to orient with their longitudinal axes extending generally radially with respect to the impeller, and generally perpendicular to the slicing knife. The impeller arrangement further includes arcuate paddles that can be installed in association with the impeller blades so as to further improve potato alignment. However, this solution serves primarily to orient a potato in a desired orientation and does not register a potato from one end with respect to the impeller.
Another proposed impeller arrangement, as disclosed in U.S. Pat. No. 4,206,671, illustrates an impeller having a series of equally spaced impeller blades radiating from a central shaft. The blades of the impeller helically curve around the shaft as they extend along the shaft to form curved, cupped sections of the blade. The curve of the blade is such that when potatoes are introduced into the impeller, the impeller blades curve away from the potatoes. In a preferred embodiment, the interior of the drum has a series of grooves formed therein to assist in aligning the food products prior to cutting. One major drawback with this impeller is the fact that due to the shape of the impeller blades, a large amount of spaced is required for the impeller. As a consequence, the housing of the rotary slicing machine must be designed accordingly, and thus existing rotary slicing machines are precluded from using such an impeller.
Yet another known variation of an impeller is illustrated in FIGS. 2-4 of the appended drawings. The impeller comprises a rear base plate 12 and a forward ring 10 permanently secured in axial spaced parallel relation to the base plate 12 by a plurality of circumferentially spaced planar paddles 14. Each paddle 14 extends inwardly generally from the peripheries of the base plate 12 and ring 10 at an oblique angle, generally α=30°, with respect to a radial plane R1 of the base plate 12. The base plate 12 preferably is provided with a central opening 18 and the forward ring 10 defines an opening 16 for receiving products to be sliced. However, this type of impeller does not sufficiently cooperate with centrifugal forces present during the rotation of the impeller so as to urge a potato axially against the forward ring 10 or the base plate 12 to thereby index the potato to enable consistent slices to be made from the potato.
Despite the solutions provided in the prior art, there still exists the need for an improved impeller that will properly align and orientate an elongate food product so as to cooperate with centrifugal forces to engage a food product with one or more fixed blades to produce a clean, flat and non-tapered series of slices. Furthermore, there still exists the need for an improved impeller that can be adapted for use in existing rotary machines.
It is therefore an object of the invention to provide an improved impeller for use with a rotary slicing machine which will orient, align and provide the necessary centrifugal force to engage a food product with one or more fixed slicing blades so as to produce a clean, flat and non-tapered series of slices.